android - Horizontal Scrollview inside appbar not working -

i wanted add horizontalscrollview appbar show number of buttons , options. googled , found out scrollview wouldn't work appbar , people had suggested using nestedscrollview , switched i'm still having lot of issues it.

here picture of happens , code have:

code:

<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" xmlns:design="http://schemas.android.com/apk/res-auto" xmlns:app="http://schemas.android.com/apk/res-auto" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" tools:context="mainactivity">  <android.support.design.widget.appbarlayout     android:id="@+id/app_bar"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:theme="@style/apptheme.appbaroverlay"     design:layout_scrollflags="scroll|snap">      <android.support.v4.widget.nestedscrollview         android:layout_width="match_parent"         android:layout_height="match_parent"         app:behavior_overlaptop="64dp"         app:layout_behavior="@string/appbar_scrolling_view_behavior">         <linearlayout             android:layout_width="wrap_content"             android:layout_height="match_parent"             android:orientation="horizontal">              <button                 android:id="@+id/button"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button5"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button4"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button3"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button2"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button7"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:layout_weight="1"                 android:gravity="bottom"                 android:text="button" />              <button                 android:id="@+id/button6"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 android:layout_gravity="bottom"                 android:layout_weight="1"                 android:gravity="bottom"                 android:text="button" />         </linearlayout>         </android.support.v4.widget.nestedscrollview>      <android.support.v7.widget.toolbar         android:id="@+id/toolbar"         android:layout_width="match_parent"         android:layout_height="?attr/actionbarsize"         android:background="?attr/colorprimary"         design:popuptheme="@style/apptheme.popupoverlay" />  </android.support.design.widget.appbarlayout>  </linearlayout> 

can please me understand i'm missing?

thank you